Figure 2.

Comparison of 2A and IRES-mediated eGFP (second gene) expression in bicistronic vectors. To compare the level of second gene product (eGFP) expressed from either eGFP, MGMT-2A-eGFP
or MGMT-IRES-eGFP vector, we transduced K562 cells with lentiviral vectors expressing
eGFP downstream of either 2A or IRES sequences as shown Figure 1. All other sequences
in the vectors were identical. K562 cells (5 × 104) were transduced once with viral particles in the range of 5, 10, 20, 50, 100 and
200 ng of p24. Seven days after the transduction, cells were analyzed by flow cytometry
for expression of eGFP. Untransduced K562 cells were used as control. Percentage of
positive cells (given as % values on histograms) and the mean fluorescence intensity
(given as numbers on histograms) were calculated using Cell Quest software.